| Relationship between drought severity and leaf photosynthetic physiological parameter variation of spring wheat |
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| DOI：10.7606/j.issn.1000-7601.2020.01.15 |
| Key Words: net photosynthesis stomatal conductance photosynthetic capacity spring wheat agricultural drought stomatal conductance model |
| Author Name | Affiliation | | ZHAO Funian | Lanzhou Institute of Arid Meteorology, China Meteorological Administration, Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province, Key Laboratory of Arid Climate Change and Disaster Reduction of CMA, Lanzhou, Gansu 730020, China | | WANG Runyuan | Lanzhou Institute of Arid Meteorology, China Meteorological Administration, Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province, Key Laboratory of Arid Climate Change and Disaster Reduction of CMA, Lanzhou, Gansu 730020, China | | ZHANG Kai | Lanzhou Institute of Arid Meteorology, China Meteorological Administration, Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province, Key Laboratory of Arid Climate Change and Disaster Reduction of CMA, Lanzhou, Gansu 730020, China | | Qi Yue | Lanzhou Institute of Arid Meteorology, China Meteorological Administration, Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province, Key Laboratory of Arid Climate Change and Disaster Reduction of CMA, Lanzhou, Gansu 730020, China | | Chen Fei | Lanzhou Institute of Arid Meteorology, China Meteorological Administration, Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province, Key Laboratory of Arid Climate Change and Disaster Reduction of CMA, Lanzhou, Gansu 730020, China | | ZHAO Hong | Lanzhou Institute of Arid Meteorology, China Meteorological Administration, Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province, Key Laboratory of Arid Climate Change and Disaster Reduction of CMA, Lanzhou, Gansu 730020, China | | Wang Heling | Lanzhou Institute of Arid Meteorology, China Meteorological Administration, Key Laboratory of Arid Climatic Change and Disaster Reduction of Gansu Province, Key Laboratory of Arid Climate Change and Disaster Reduction of CMA, Lanzhou, Gansu 730020, China |
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| Abstract: |
| Quantifying drought severity plays critical role in agricultural drought monitoring, crop modeling and irrigation scheduling. In this study, dry\|down experiments for spring wheat were carried out in plots and buckets. The responses of several photosynthetic parameters, including net photosynthesis (Pn), stomatal conductance (gssat), ratio of intercellular CO2 to atmospheric CO2 (Ci/Ca), maximum carboxylation rate of Rubisco (Vcmax) and maximum rate of electron transport (Jmax), to water supply condition were analyzed. Meanwhile, the relations between different photosynthetic parameters under different water conditions were also determined, especially the relationship between Pn and gssat and the impacts of drought on parameters for three typical semi\|empirical stomatal conductance models. The results showed that there were no significantly variation for the photosynthetic parameters until available soil water content (ASWC) was less than 0.5. The parameters gssat, Ci/Ca and Pn sequentially decreased as ASWC decreased from 0.5 to 0.3. The relation of Pn, gssat and Ci/Ca were stable while ASWC ranged from 0.5 to 0.3. The parameters gssat, Vcmax and Jmax decreased in linear form with ASWC when ASWC was less than 0.3. Meanwhile, the relationship between Pn and gssat changed in the range of ASWC from 0.5 to 0.3, hence the slope of semi\|empirical stomatal conductance model. However, when ASWC was smaller than 0.1, Ci/Ca increased with ASWC, and Pn decreased as Ci/Ca increased. Based on the responses of different photosynthetic parameters to water supply condition, four stages of drought development for spring wheat apparently existed. As ASWC was greater than 0.5 and gssat greater than 0.35 mol·m-2·s-1, there was not drought or drought was very slight. The gssat mainly limited Pn during ASWC ranged from 0.3 to 0.5 and gssat varied from 0.15 to 0.35 mol·m-2·s-1. However, non\|stomatal conductance started to impact Pn as ASWC changed from 0.1 to 0.3 (gssat ranged from 0.06 to 0.15 mol·m-2·s-1). As ASWC was less than 0.1, gssat was smaller than 0.06 mol·m-2·s-1 and the apparatus for photosynthesis might suffer injury. |
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